As universally known, a colony of honeybees consists of one queen bee devoted to laying eggs in the cells, a few male bees (drones) for mating with the queen bee, and a large number of worker bees which are female but sexually imperfect. The queen bee gives pheromone to worker bees to neutralize them sexually and, at the same time, leads the colony. The worker bees, by producing royal jelly, help the queen bee in promoting her ovarial development and activating her fertility and the larvae (grubs) in attaining growth. The worker bees, which have a lifespan of about one month after emergence, spend about 20 days immediately following emergence in cleaning the cells and the honeycomb as a whole, feeding the queen bee and the larvae with royal jelly, building the honeycomb, and storing pollen and honey, and spend about 10 remaining days in going out of the honeycombs in search of pollen and nectar in preparation for the winter season. The pollen and nectar they collect pass on to the younger worker bees for storage in the cells. During their entire life, the worker bees defend the colony against attack by enemies.
Artificial beekeeping for collection of honey and pollination of plants makes use of the aforementioned habits of honeybees.
In conventional artificial beekeeping, a thin waxplate, press-formed with hexagonal cells on both sides, is fixed within a frame and this frame is hung inside the hive at the honeybees' hive-building period, thus encouraging the honeybees to build cells on the opposite sides of the waxplate (foundation) and complete a honeycomb for storage of eggs, larvae, pollen, and honey, and then hanging a multiplicity of such honeycombs in the hive so that the honeybees can maintain the colony. While the cells so built by the honeybees are chiefly for use by the worker bees, cells of a slightly larger cross-sectional area than those for the worker bees are also built at corners of the honeycomb for accommodating male bees.
The cells the honeybees build on the opposite sides of each foundation for use by the worker bees have a cross-sectional area large enough for the worker bees to crawl into head on for tending to the larvae and storing pollen and honey and also large enough to allow the queen bee to insert her abdomen for laying eggs. The depth of the cells from their entrances to the foundation is such that the leading end of the ovipositor of the queen bee reaches the foundation when the queen bee thrusts her abdomen in the cell. This depth generally runs in the range of 12 to 14 mm, though it is variable with the size of the honeybees depending on their species.
Whenever the cells are emptied in consequence of emergence, younger worker bees clean the interiors of the empty cells to prepare them for the queen bee to lay eggs therein as by removing dead bees, dead eggs, dead larvae or other debris from the cells and discard them outside of the hive. They tend to larvae hatched from eggs by feeding them with royal jelly, fly out of the hive to receive the pollen and nectar brought home by older worker bees, and store them in the cells set aside exclusively for this purpose. In each of the empty cells already cleaned by the younger worker bees, the queen bee inserts her abdomen until the leading end of her ovipositor reaches the foundation and lays one egg. The eggs so laid hatch in about three days. During the three-day interval, the eggs are enveloped with royal jelly by the worker bees. After the hatching, the larvae feed on the royal jelly until they grow into pupas. About 21 days after they are laid, they come out of the cells as imagines.
As the number of worker bees gradually increases and substantially all the cells of the honeycombs in the hive are filled with eggs, larvae, pupas, honey, and pollen, there arises a shortage of cells available for laying eggs. Thus, the queen bee contracts what is called "neurosis" and suffers from insufficient secretion of pheromone to be given to the worker bees and loses in power to lead worker bees. Owing to the shortage of cells for storage of pollen and honey, the worker bees come to devote less efforts to the chore of nectar collection. A group of bees develop the swarming fever and the worker bees prepare to support a new queen bee. The old queen bee, accompanied by a bunch of worker bees selected from the group of honeybees loyal to her, swarms. Consequently, the colony of honeybees is divided into two new colonies. Each of the two colonies resulting from the swarm has an insufficient number of worker bees and, therefore, suffers from deficiency in nectar-collecting capacity, this situation continues until the number of worker bees has increased sufficiently.
It has been customary to solve this problem by removing the upper lid of the hive when all the cells of the honeycombs within the hive become substantially saturated, covering the open upper end of the hive with a partition (queen excluder) enabling the worker bees and not the queen bee to crawl therethrough, superposing a super-hive on the partition, suspending honeycomb made by honeybees inside the super-hive, and allowing the worker bees to store pollen and honey in the cells on the honeycomb in the super-hive.
It has been generally held that owing to the measure described above, the worker bees are precluded from developing swarming fever because they are enabled to crawl through the queen excluder, clean the cells in the lower hive, tend the larvae, receive pheromone from and give royal jelly to the queen bee and, at the same time, store pollen and honey in the cells of the honeycombs in the super-hive, while the queen bee is allowed to lay eggs only in the empty cells in the lower hive which have already been cleaned by the worker bees and, therefore, the otherwise inevitable excessive increase of the number of worker bees in one group is avoided.
It is exclusively in the cells in the lower hive which have been emptied as by emergence and then cleaned by worker bees in the honeycombs that the queen bee is allowed to lay her eggs. In the circumstance, the queen bee's urge to lay eggs is not satisfied and her secretion of pheromone meant for worker bees dwindles with her contraction of neurosis and the worker bees are psychologically disturbed by the frustration they feel upon not receiving sufficient pheromone from the queen bee. In short, both the queen bee and the worker bees suffer from frustration and the overall nectar-collecting capacity of the honeybees of the colony becomes deficient, possibly with the result that some of the worker bees develop swarming fever and proceed to swarm. The question as to whether or not the worker bees have developed swarming fever cannot be definitely answered unless the super-hive and the queen excluder are removed and the honey bees in the lower hive are visually examined. Thus, the beekeeping by the method under discussion takes much time and labor.
To avoid this trouble, there has been developed and adopted a practice of superposing a super-hive on the basic hive without using a queen excluder, suspending five to seven honeycombs made by honeybees and one feeder within a hive having a capacity for ten honeycombs, for example, suspending nine honeycombs within the super-hive, allowing the honey bees to build honeycombs of their own in the spaces remaining inside the hives and preventing them from developing swarming fever and, when the honeycombs are completed, removing the completed honeycombs, and collecting beewax from the honeycombs. This method, however, has the following disadvantage.
During the season when nectar is available first from rape-seed and then from lotus, buck-eye, acacia, and the like, the worker bees tend to store honey in the upper cells so that the upper cells of the super-hive become filled with honey, giving the queen bee no choice but to lay eggs in the empty lower cells. This leads to a favorable situation inasmuch as only 20 to 30% of the cells in the super-hive ordinarily come to be occupied by the larvae. In recent years in Japan, however, there has been a considerable increase in the number of honeybee colonies being kept so that the amount of honey that can be collected by an individual colony has decreased. Thus, even when a super-hive is provided, 70 to 80% of the cells come to be occupied by the larvae. This increase in number of the larvae leads to a number of problems. One of these is that the honeybees are more apt to develop swarming fever and another is that since the temperature of the cells occupied by the larvae is kept high, it may result in the death of a substantial percentage of the larvae during the travel of the hives in their sealed state. Moreover, the young house worker bees will consume large amounts of honey and pollen, decreasing the amount that is stored, and the number of workers will vary greatly from season to season. Therefore, the aforesaid beekeeping method can hardly be called an efficient one during times when the amount of nectar available is limited, as is the case nowadays. Fundamentally, therefore, it has become necessary to develop a method for controlling the number of worker bees.